Real-time tsunami risk evaluation method by synthetic dynamics and Bayesian update
Real-time tsunami risk evaluation method by synthetic dynamics and Bayesian update
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综合动力学和贝叶斯更新的实时海啸风险评估方法
DOI：
10.11421/jsces.2022.20220003
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发表时间：
2022
影响因子：
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通讯作者：
橋詰 正広
中科院分区：
文献类型：
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作者：
野村 怜佳;藤田 真粹;大竹 雄;森口 周二;越村 俊一;寺田 賢二郎;橋詰 正広
本研究提出一种结合本征正交分解（POD）与贝叶斯更新的实时海啸风险评估方法。通过南海海槽事件引起的海啸的数值算例，验证了该方法的有效性。首先，对由各种断层破裂模式确定的可能的海啸情景进行海啸模拟，并在选定的合成测点存储波高的时间历程。然后，POD被应用到由动力学模式和系数组成的综合动力学（SD）的结果数据矩阵，后者代表了特定的信息。在实时风险评估阶段，一个实际的海啸事件的波序列依次测量在合成测量点，并用于估计相应的动力学系数的构建SD。同时，通过贝叶斯更新的应用，在每个时间评估为选定的海啸情景预先计算的每个动力学系数的可能性，并顺序更新以检测最可能的情景。最后，预先计算的海啸到达时间和淹没深度分布对应的检测到的情况下，确定为海啸发生后7分钟的风险评估指标。
This study presents a method of real-time tsunami risk evaluation by combined use of proper orthogonal decomposition (POD) and Bayesian update. The validity of the proposed method is demonstrated through the numerical example targeting plausible tsunamis induced by Nankai-Trough events. First, tsunami simu-lations are carried out for plausible tsunami scenarios determined by various patterns of fault rupture, and the time histories of wave heights are stored at selected synthetic gauge points. Then, POD is applied to the re-sulting data matrix of the synthetic dynamics (SD) composed of dynamics modes and coefficients, the latter of which represent scenario-specific information. In the real-time risk evaluation phase, the wave sequences of an actual tsunami event are sequentially measured at the synthetic gauge points and used to estimate the corresponding dynamics coefficients of the constructed SD. At the same time, by the application of Bayesian update, the likelihood of each of the dynamics coefficients pre-calculated for the selected tsunami scenarios is evaluated at each time and sequentially updated to detect the most probable scenario. Finally, the pre-calculated tsunami arrival time and inundation depth distribution corresponding to the detected scenario are determined as risk assessment indices seven minutes after the tsunami generation.